#include <string.h>
#include <stdio.h>

int main ()
{
	char *a = "abcefgh";
	char *b = "bc";
	char *d = "be";
	char *c = strstr(a, b);
	char *e = strstr(a, d);
	printf("c=== %s \n", c);		// output: bcefgh
	printf("e=== %s \n", e);		// output: NULL
}